.sub-sidebar {
    left: 0;
    top: 0;
    bottom: 0;
    position: fixed;
    width: 18%; 
    overflow: hidden;
    margin-left: 100px;
    background-color: $sub-sidebar-bg;
    border-right: 1px solid $sub-sidebar-border-color; 
    min-height: calc(100vh - 0px);
}